Apr 29

Bixenon low beam and halogen high beam relay wiring

Hi guys,

I've been pondering this for a few months and every time I try to work out what should be wired to what, I confuse myself and walk away!

I've recently upgraded from mh1 5.0s and put some mini d2s 4.0s into my BMW 3 series (E46 pre facelift).
I wired up the bixenon solenoid to a splitter connected to the factory halogen high beams. This works just fine, and was quite exciting as I never had it hooked up with my mh1's as the shutter always used to stick or return to the incorrect spot after hitting the high beams, thus causing a blurry cutoff.

What I've been trying to achieve is this...

When the xenon low beams are on:
- Only the bixenon shutter is used when using high beam
- The factory halogen high beam is not used

When the xenon low beams are off:
- Only the factory halogen high beam is used
- The bixenon shutter on the projector is not used (although this is quite irrelevant as whether its activated in this instance or not has no visual outcome, since the low beams will be off).

I want to achieve this as I basically do not want dual high beams (I can hear some people shouting 'why?!'), and would like a more controlled and calculated use of the high beam capabilities that are currently installed.

I am lead to believe I can achieve this using a SPDT relay, but what needs wiring to what? This is where I'd love some guidance.

Thanks for any help,